1. Field of the Invention
The present invention relates generally to Power over Ethernet (PoE) and, more particularly, to a system and method for pre-detection in a PoE system.
2. Introduction
The IEEE 802.3af and 802.3 at PoE specifications provide a framework for delivery of power from power sourcing equipment (PSE) to a powered device (PD) over Ethernet cabling. In this framework, various PDs can be deployed such as voice over IP (VoIP) phones, wireless LAN access points, network cameras, computing devices, etc.
In a conventional PoE process, a valid device detection is first performed. This detection process identifies whether or not it is connected to a valid PoE device. As part of this process, the typical detection process can present voltages of up to 30V for up to 200 ms if no valid PD is connected to the RJ45 connector. This voltage can be potentially damaging to equipment connected to the port. What is needed therefore is a protection mechanism for the PD detection process.